Many conventional image processing systems utilize a camera in conjunction with a video display. FIG. 1 shows an example of such an arrangement in the form of an image processing system 100 which includes a camera 102 and a separate display 104. The system 100 may be used in a video conferencing application or other suitable application in which the camera 102 generates an image of an on-site user 106 and the display 104 presents images of one or more remote users to the user 106.
A significant problem that can arise in the system 100 of FIG. 1 is that it is difficult to configure the camera 102 and display 104 such that it appears to both the on-site and remote users that they are making eye contact via the generated images. This eye contact problem is a result of misalignment between the optical axis of the camera 102 and a normal to the display 104. In the system 100, the camera 102 and display 104 are typically located as close together as possible in order to minimize this effect. However, in applications such as portable video conferencing units and human-machine interfaces, users often locate themselves very close to the display, such that the eye contact problem is accentuated.
U.S. Pat. No. 5,666,155 entitled “Eye Contact Video Telephony” discloses an approach for addressing the eye contact problem described above. In this approach, a video camera is located behind a display screen and generates images of a user looking at the screen. Displayed images are directed to the user via an array of lenses in the display screen, so as to create an illusion of eye contact. Unfortunately, this approach requires placement of a video camera at a particular distance behind the display screen, which can substantially increase the size of the system. In addition, such an approach is unable to avoid certain important types of image-related distortion, such as the so-called “fish eye” distortion which results in a single-camera system when a user is situated close to the display.